Oct. 24, 2013 USC scientist Qi-Long Ying and a team of researchers have long been searching for biotech's version of the fountain of youth -- ways to encourage embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs) to endlessly self-renew, or divide to produce more stem cells.

In a pair of studies published in Nature Communications in September and in The EMBO Journal in August, Ying and his team revealed some of the ways that ESCs and EpiSCs retain their pluripotency, or ability to differentiate into virtually any kind of cell.

The study in Nature Communications identified a novel way of culturing human ESCs by focusing on the Wnt/beta-catenin signaling pathway -- a group of molecules that work together to control various cell functions, including some related to embryonic development.

According to the researchers, this pathway can prompt mouse EpiSCs and human ESCs to either self-renew or differentiate. When the protein beta-catenin remains within the cell cytoplasm but outside of the nucleus, the stem cell continues to self-renew. When beta-catenin moves into a stem cell's nucleus, differentiation begins.

The paper published in The EMBO Journal addresses mouse ESCs, which are derived from the embryo at an earlier stage and are more pluripotent than mouse EpiSCs.

The study revealed the important role of Tfcp2l1 -- a transcription factor, or protein that controls which genes are turned on and off in a cell.

In mice, Tfcp2l1 helps communicate to ESCs that they should self-renew. The transcription factor also shows promise for "rewinding" slightly more differentiated EpiSCs into the more nave ESC state.

By learning more about the ESC and EpiSC playbooks, Ying and his colleagues can better control stem cell self-renewal, offering hope for patients with currently untreatable diseases and creating potential for a wide variety of other applications.

"These new findings have allowed us to develop conditions for the efficient propagation of human ESCs, and might also enable us to establish pluripotent stem cells from different species," said Ying, associate professor of stem cell biology and regenerative medicine at the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC. "This has far-reaching implications for a variety of applied areas of investigation, ranging from manipulating the genomes of agricultural animals to developing stem cell-based therapies for ailments such as Parkinson's disease or spinal cord injuries."

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Researcher reveals how to better master stem cells' fate

redOrbit Staff & Wire Reports Your Universe Online

For the first time, scientists from the Salk Institute for Biological Studies have taken stem cells from chimpanzees and bonobos and turned them into induced pluripotent stem cells (iPSCs), and their work has helped to highlight some of the differences between humans and non-human primates.

This type of cell, which has the ability to form any other type of cell or tissue in the body, can be used to model diseases that would normally be difficult to obtain from a living person or animal, the researchers said. The Salk Institute team, however, is using the iPSCs to compare and contrast the cells of humans with those of our closest living relatives the great apes with whom we share about 99 percent of our genome.

Comparing human, chimpanzee and bonobo cells can give us clues to understand biological processes, such as infection, diseases, brain evolution, adaptation or genetic diversity, senior research associate Iigo Narvaiza explained. Until now, the sources for chimpanzee and bonobo cells were limited to postmortem tissue or blood. Now you could generate neurons, for example, from the three different species and compare them to test hypotheses.

Narvaiza and senior staff scientist Carol Marchetto studied the iPSCs obtained from the great ape species. After comparing them to human stem cells, they discovered disparities in the regulation of so-called jumping genes or transposons DNA elements that can essentially copy and paste themselves into various locations in the genome between the two types of creatures.

These so-called jumping genes give scientists a way to quickly shuffle DNA, and could possibly be shaping the way in which our genomes evolve, the study authors said. They found genes that are differentially expressed between human iPSCs and similar cells from both chimpanzees and bonobos.

To the groups surprise, two of those genes code for proteins that restrict a jumping gene called long interspersed element-1, or L1 for short, the researchers reported. Compared with non-human primate cells, human iPSCs expressed higher levels of these restrictors, called APOBEC3B and PIWIL2.

L1 and a handful of other jumping genes are abundant throughout our genomes. Where these bits of DNA insert themselves is hard to predict, and they can produce variable effects. For example, they might completely disrupt genes, modulate them, or cause them to be processed into entirely new proteins, they added.

Using L1 that was tagged with a fluorescent marker, Narvaiza, Marchetto and their associates observed lower numbers of fluorescent iPSCs from humans than from non-human primates. In further research, the team produced iPSCs that had either too much or too little APOBEC3B and PIWIL2, and as they expected, elevated levels of those proteins hampered the mobility and reduced the appearance of DNA that had just been inserted into the ape cells.

These results suggested that L1 elements insert themselves less often throughout our genomes. Indeed, looking at genomes of humans and chimpanzees that had already been sequenced, the researchers found that the primates had more copies of L1 sequences than did humans, the Institute explained. The question that remains is, what would be the impact of differences in L1 regulation?

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Stem Cells Reveal Key Differences Between Apes And Humans

TORONTO, ON University of Toronto researchers have developed a method that can rapidly screen human stem cells and better control what they will turn into. The technology could have potential use in regenerative medicine and drug development. Findings are published in this weeks issue of the journal Nature Methods.

The work allows for a better understanding of how to turn stem cells into clinically useful cell types more efficiently, according to Emanuel Nazareth, a PhD student at the Institute of Biomaterials & Biomedical Engineering (IBBME) at the University of Toronto. The research comes out of the lab of Professor Peter Zandstra, Canada Research Chair in Bioengineering at U of T.

The researchers used human pluripotent stem cells (hPSC), cells which have the potential to differentiate and eventually become any type of cell in the body. But the key to getting stem cells to grow into specific types of cells, such as skin cells or heart tissue, is to grow them in the right environment in culture, and there have been challenges in getting those environments (which vary for different types of stem cells) just right, Nazareth said.

The researchers developed a high-throughput platform, which uses robotics and automation to test many compounds or drugs at once, with controllable environments to screen hPSCs in. With it, they can control the size of the stem cell colony, the density of cells, and other parameters in order to better study characteristics of the cells as they differentiate or turn into other cell types. Studies were done using stem cells in micro-environments optimized for screening and observing how they behaved when chemical changes were introduced.

It was found that two specific proteins within stem cells, Oct4 and Sox2, can be used to track the four major early cell fate types that stem cells can turn into, allowing four screens to be performed at once.

One of the most frustrating challenges is that we have different research protocols for different cell types. But as it turns out, very often those protocols dont work across many different cell lines, Nazareth said.

The work also provides a way to study differences across cell lines that can be used to predict certain genetic information, such as abnormal chromosomes. Whats more, these predictions can be done in a fraction of the time compared to other existing techniques, and for a substantially lower cost compared to other testing and screening methods.

We anticipate this technology will underpin new strategies to identify cell fate control molecules, or even drugs, for a number of different stem cell types, Zandstra said.

As a drug screening technology its a dramatic improvement over its predecessors, said Nazareth. He notes that in some cases, the new technology can drop testing time from up to a month to a mere two days.

Professor Peter Zandstra was awarded the 2013 Till & McCulloch Award in recognition of this contribution to global stem cell research.

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Predicting the fate of stem cells - Technique has potential use in regenerative medicine and drug development

PARIS: A woman who received a donor windpipe seeded with her own stem cells, is living healthily after the groundbreaking surgery five years ago, said a report in medical journal The Lancet.

"These results confirm what we, and many patients, hoped at the time of the original operation: that tissue engineered transplants are safe and effective in the long term," said Paolo Macchiarini who led the surgical team.

The journal hailed progress in tissue engineering when reporting the success of the surgery involving stem cells, which are immature cells that can 'grow' into specialised cells that can comprise and maintain the human body.

Donor windpipes are often rejected by the recipient's immune system, while patients also suffer the uncontrolled die-off of cells, called necrosis, and bleeding.

In the 2008 procedure performed on Claudia Castillo, the use of stem cells from the patient was tested to find out if the risk of attack by the immune system would be reduced.

The then 30-year-old woman who suffered from tuberculosis, received a new lease on life with the transplant that involved removing cells from a section of a donor windpipe and grafting cartilage cells grown from her own stem cells onto it.

Other cells taken from a healthy part of her windpipe were also used in the operation that saw the patient being discharged from hospital 10 days later.

The surgical team, led by Paolo Macchiarini from Stockholm's Karolinska University Hospital, could only determine the success of the operation through long-term follow-ups with the patient.

"The recipient continues to enjoy a good quality of life, and has not experienced any immunological complications or rejection of the implanted airway," said the findings published in The Lancet medical journal.

The report also noted that the patient continues to enjoy "a normal social and working life".

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Windpipe created from stem cells a success

By a News Reporter-Staff News Editor at Stem Cell Week -- A new study on Stem Cell Research is now available. According to news reporting from Chongqing, People's Republic of China, by NewsRx journalists, research stated, "The purpose of this study was to investigate the influences of nanoscale wear particles derived from titanium/titanium alloy-based implants on integration of bone. Here we report the potential impact of titanium oxide (TiO2) nanoparticles on adhesion, migration, proliferation, and differentiation of mesenchymal stem cells (MSC) from the cellular level to the molecular level in the Wistar rat."

The news correspondents obtained a quote from the research from Chongqing University, "A series of TiO2 nanoparticles (14 nm, 108 nm, and 196 nm) were synthesized and characterized by scanning electron microscopy and transmission electron microscopy, respectively. The TiO2 nanoparticles had negative effects on cell viability, proliferation, and the cell cycle of MSC in a dose-dependent and size-dependent manner. Confocal laser scanning microscopy was used to investigate the effects of particle internalization on adhesion, spreading, and morphology of MSC. The integrity of the cell membrane, cytoskeleton, and vinculin of MSC were negatively influenced by large TiO2 nanoparticles. The Transwell migration assay and a wound healing model suggested that TiO2 nanoparticles had a strong adverse impact on cell migration as particle size increased (P < 0.01)."

According to the news reporters, the research concluded: "Furthermore, alkaline phosphatase, gene expression of osteocalcin (OC) and osteopontin (OPN), and mineralization measurements indicate that the size of the TiO2 nanoparticles negatively affected osteogenic differentiation of MSC."

For more information on this research see: Effects of titanium nanoparticles on adhesion, migration, proliferation, and differentiation of mesenchymal stem cells. International Journal of Nanomedicine, 2013;8():3619-3630. International Journal of Nanomedicine can be contacted at: Dove Medical Press Ltd, PO Box 300-008, Albany, Auckland 0752, New Zealand (see also Stem Cell Research).

Our news journalists report that additional information may be obtained by contacting Y.H. Hou, Chongqing Univ, Coll Bioengn, Minist Educ, Chongqing 400044, People's Republic of China. Additional authors for this research include K.Y. Cai, J.H. Li, X.Y. Chen, M. Lai, Y. Hu, Z. Luo, X.W. Ding and D.W. Xu.

Keywords for this news article include: Asia, Titanium, Chongqing, Light Metals, Stem Cell Research, People's Republic of China

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2013, NewsRx LLC

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Investigators from Chongqing University Target Stem Cells

Oct. 23, 2013 Researchers at the Salk Institute for Biological Studies have, for the first time, taken chimpanzee and bonobo skin cells and turned them into induced pluripotent stem cells (iPSCs), a type of cell that has the ability to form any other cell or tissue in the body.

Mouse iPSCs were created in 2006 by Kazutoshi Takahashi and Shinya Yamanaka at Kyoto University in Japan, and human iPSCs soon followed -- -feats which earned Yamanaka the Nobel Prize in Physiology or Medicine last year. Now scientists regularly use iPSCs to model diseases using cells that would be otherwise difficult to obtain from a living person or animal. By adding a combination of four key factors, a skin cell can be made into an iPSC, which can then be coaxed into forming liver, lung and brain cells in a culture dish.

It's now possible to not only model disease using the cells, but also to compare iPSCs from humans to those of our closest living relatives -- -great apes, with which we share a majority of genes -- -for insight into what molecular and cellular features make us human.

"Comparing human, chimpanzee and bonobo cells can give us clues to understand biological processes, such as infection, diseases, brain evolution, adaptation or genetic diversity," says senior research associate Iigo Narvaiza, who led the study with senior staff scientist Carol Marchetto at the Salk Institute in La Jolla. "Until now, the sources for chimpanzee and bonobo cells were limited to postmortem tissue or blood. Now you could generate neurons, for example, from the three different species and compare them to test hypotheses."

In the new study, published online October 23 in the journal Nature, scientists found disparities in the regulation of jumping genes or transposons -- -DNA elements that can copy and paste themselves into spots throughout the genome -- between humans and non-human primate cells. Jumping genes provide a means to rapidly shuffle DNA and might be shaping the evolution of our genomes, the scientists say.

Working in the lab of Salk's Fred Gage, the Vi and John Adler Chair for Research on Age-Related Neurodegenerative Disease, Narvaiza, Marchetto and their colleagues identified genes that are differentially expressed between iPSCs from humans and both chimpanzees and bonobos.

To the group's surprise, two of those genes code for proteins that restrict a jumping gene called long interspersed element-1or L1, for short. Compared with non-human primate cells, human iPSCs expressed higher levels of these restrictors, called APOBEC3B and PIWIL2. "We weren't expecting that," Marchetto says. "Those genes caught our eyes, so they were the first targets we focused on."

L1 and a handful of other jumping genes are abundant throughout our genomes. Where these bits of DNA insert themselves is hard to predict, and they can produce variable effects. For example, they might completely disrupt genes, modulate them, or cause them to be processed into entirely new proteins.

Using L1 tagged with a fluorescent marker, the group observed higher numbers of fluorescent iPSCs from non-human primates compared with humans. In separate experiments, they produced iPSCs with too much or too little APOBEC3B and PIWIL2, finding -- -as expected -- -that an excess of the two proteins dampened the mobility and reduced the appearance of newly inserted DNA in the non-human primate cells.

These results suggested that L1 elements insert themselves less often throughout our genomes. Indeed, looking at genomes of humans and chimpanzees that had already been sequenced, the researchers found that the primates had more copies of L1 sequences than did humans.

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Induced pluripotent stem cells reveal differences between humans and great apes

BERKELEY Bioengineers at the University of California, Berkeley, have shown that physical cues can replace certain chemicals when nudging mature cells back to a pluripotent stage, capable of becoming any cell type in the body.

The researchers grew fibroblasts cells taken from human skin and mouse ears on surfaces with parallel grooves measuring 10 micrometers wide and 3 micrometers high. After two weeks of culture in a special cocktail used to reprogram mature cells, the researchers found a four-fold increase in the number of cells that reverted back to an embryonic-like state compared with cells grown on a flat surface. Growing cells in scaffolds of nanofibers aligned in parallel had similar effects.

The study, published online Sunday (Oct. 20) in the journal Nature Materials, could significantly enhance the process of reprogramming adult cells into embryonic-like stem cells that can differentiate, or develop, into any type of tissue that makes up our bodies.

The 2012 Nobel Prize in Physiology or Medicine was awarded to scientists who discovered that it was possible to reprogram cells using biochemical compounds and proteins that regulate gene expression. These induced pluripotent stem cells have since become a research mainstay in regenerative medicine, disease modeling and drug screening.

"Our study demonstrates for the first time that the physical features of biomaterials can replace some of these biochemical factors and regulate the memory of a cell's identity," said study principal investigator Song Li, UC Berkeley professor of bioengineering. "We show that biophysical signals can be converted into intracellular chemical signals that coax cells to change."

The current process for reprogramming cells relies on a formula that uses a virus to introduce gene-altering proteins into mature cells. Certain chemical compounds, including valproic acid, that can dramatically affect global DNA structure and expression are also used to boost the efficiency of the reprogramming process.

"The concern with current methods is the low efficiency at which cells actually reprogram and the unpredictable long-term effects of certain imposed genetic or chemical manipulations," said study lead author Timothy Downing, who did this research as a graduate student in the UC Berkeley-UC San Francisco Joint Graduate Program in Bioengineering. "For instance, valproic acid is a potent chemical that drastically alters the cell's epigenetic state and can cause unintended changes inside the cell. Given this, many people have been looking at different ways to improve various aspects of the reprogramming process."

Previous studies have shown that physical and mechanical forces can influence cell fate, but the effect on epigenetic state and cell reprogramming had not been clear.

The new study found that culturing cells on micro-grooved biomaterials improved the quality and consistency of the reprogramming process, and was just as effective as valproic acid.

"Cells elongate, for example, as they migrate throughout the body," said Downing, who is now a research scientist in Li's lab. "In the case of topography, where we control the elongation of a cell by controlling the physical microenvironment, we are able to more closely mimic what a cell would experience in its native physiological environment. In this regard, these physical cues are less invasive and artificial to the cell and therefore less likely to cause unintended side effects."

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From mature cells to embryonic-like stem cells

PUBLIC RELEASE DATE:

22-Oct-2013

Contact: Erin Vollick Comm.ibbme@utoronto.ca 416-946-8019 University of Toronto

University of Toronto researchers have developed a method that can rapidly screen human stem cells and better control what they will turn into. The technology could have potential use in regenerative medicine and drug development. Findings are published in this week's issue of the journal Nature Methods.

"The work allows for a better understanding of how to turn stem cells into clinically useful cell types more efficiently," according to Emanuel Nazareth, a PhD student at the Institute of Biomaterials & Biomedical Engineering (IBBME) at the University of Toronto. The research comes out of the lab of Professor Peter Zandstra, Canada Research Chair in Bioengineering at U of T.

The researchers used human pluripotent stem cells (hPSC), cells which have the potential to differentiate and eventually become any type of cell in the body. But the key to getting stem cells to grow into specific types of cells, such as skin cells or heart tissue, is to grow them in the right environment in culture, and there have been challenges in getting those environments (which vary for different types of stem cells) just right, Nazareth said.

The researchers developed a high-throughput platform, which uses robotics and automation to test many compounds or drugs at once, with controllable environments to screen hPSCs in. With it, they can control the size of the stem cell colony, the density of cells, and other parameters in order to better study characteristics of the cells as they differentiate or turn into other cell types. Studies were done using stem cells in micro-environments optimized for screening and observing how they behaved when chemical changes were introduced.

It was found that two specific proteins within stem cells, Oct4 and Sox2, can be used to track the four major early cell fate types that stem cells can turn into, allowing four screens to be performed at once.

"One of the most frustrating challenges is that we have different research protocols for different cell types. But as it turns out, very often those protocols don't work across many different cell lines," Nazareth said.

The work also provides a way to study differences across cell lines that can be used to predict certain genetic information, such as abnormal chromosomes. What's more, these predictions can be done in a fraction of the time compared to other existing techniques, and for a substantially lower cost compared to other testing and screening methods.

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Predicting the fate of stem cells